Embodiments of the invention described herein relate generally to isotope production systems, and more particularly to isotope production systems that may be safely used in relatively confined spaces, such as hospital rooms.
Radioisotopes (also called radionuclides) have several applications in medical therapy, imaging, and research, as well as other applications that are not medically related. Systems that produce radioisotopes typically include a particle accelerator, such as a cyclotron, that has a magnet yoke that surrounds an acceleration chamber. The acceleration chamber may include opposing pole tops that are spaced apart from each other. Electrical and magnetic fields may be generated within the acceleration chamber to accelerate and guide charged particles along a spiral-like orbit between the poles. To produce the radioisotopes, the cyclotron forms a beam of the charged particles and directs the particle beam out of the acceleration chamber and toward a target system having a target material. The particle beam is incident upon the target material thereby generating radioisotopes.
During operation of an isotope production system, large amounts of radiation (i.e., unhealthy levels of radiation for individuals nearby) may be generated within the target system and, separately, within the cyclotron. For example, with respect to the target system, radiation from neutrons and gamma rays may be generated when the beam is incident upon the target material. With respect to the cyclotron, ions within the acceleration chamber may collide with gas particles therein and become neutral particles that are no longer affected by the electrical and magnetic fields within the acceleration chamber. These neutral particles, in turn, may collide with the walls of the acceleration chamber and produce secondary gamma radiation. To protect nearby individuals from the radiation (e.g., employees or patients of a hospital), isotope production systems may use shields to attenuate or block the radiation.
In some conventional isotope production systems, radiation leakage has been addressed by adding a large amount of shielding that surrounds both the cyclotron and the target system. However, the large amounts of shielding may be costly and too heavy for the rooms where the isotope production system are to be located. Alternatively or in addition to the large amounts of shielding, isotope production systems may be located within a specially designed room or rooms. For example, the cyclotron and the target system may be in separate rooms or have large walls separating the two. However, designing specific rooms for isotope production systems raises new challenges, especially for pre-existing rooms that were not originally intended for radioisotope production.
Yet another challenge presented by radiation leakage is how to remove the isotope production system when, for example, it is replaced or moved to another location. Decommissioning an isotope production system includes safely disassembling the system and removing and storing the radioactive parts and materials. Another concern is decontaminating the room where the isotope production system was located. In some instances, original support structures of the room, such as floors, ceilings, and walls, must be removed because the support structures have been contaminated by radioactivity. Such decommissioning and decontaminating procedures can be costly and time-consuming.
Accordingly, there is a need for methods, cyclotrons, and isotope production systems that reduce radiation exposure to individuals in the room or nearby area. Furthermore, there is a need for isotope production systems that may be more easily decommissioned than known systems.